Gas lift valve



Oct. 12, 1954 CHURCH 2 691,383

GAS LIFT VALVE Filed July 26, 1950 ./40 I z Z 5 ix I' 3 2 54 e) 59 60 55g 158 @Q Fig.2

Walter 1.. Church Fig 4 v INVEN TOR.

Attorney- Patented Oct. 12, 1954 UNITED STATES PATENT OFFICE GAS LIFTVALVE Walter L. Church, Houston, Tex. Application July 26, 1950, SerialN 0. 176,011

3 Claims. 1

.This invention pertains to valves and to a system of valves used foradmitting gas to a column of liquid for lifting same. More particularlyit pertains to such valves used in conjunction with a system of gas liftfor raising petroleum fluids in an oil well whose natural pressure isinsufficient to accomplish the purpose satisfactorily. The valve andsystem are intended to be used to unload the well by admitting gassuccessively first near the top of the oil column, then lower and lowerto the desired depth, removing or lightening the oil above each valvebefore admitting gas to the next lower valve, so that the gas pressurerequired for removing the oil will not have to be greater than thehydrostatic pressure of the whole column of that oil standing in thewell initially but need only be greater than that of the column of deadoil standing between the two valves spaced farthest apart plus, in thecase of continuous operation, the head of light gas-oil emulsionthereabove. This system of unloading a well with a plurality of spacedvalves is known as stage lift. After the well has been unloaded the gascan be admitted continuously or intermittently to the bottom of thecolumn depending on the rate of flow of the oil from the sand and thepressure thereof and the depth of the well and other factors.

An object of this invention is to provide a. stage lift valve and systemwhich will have a long and satisfactory operating life and to this endit is an object of the invention to provide a valve which will noteasily be out by fluid flow therethrough and a system of valves suchthat the valves will not have to'operate in a partially open conditionfor any great length of time.

A further object of the invention is to provide a valve which isinexpensive to manufacture and reliable in operation and to these endsit is an object to provide a valve that is sturdy yet simple inconstruction.

Other objects and advantages of the invention will become apparent fromthe following description thereof.

For a detailed description of a preferred embodiment of the invention,reference will now be had to the accompanying drawings in which Figure 1is a. vertical section through an oil well showing valves according tothe invention for continuous gas lift;

Figure 2 is a vertical section through one of the valves, taken on line2-2 of Figure 3;

Figure 3 is a horizontal section. taken on line. 3-3 of Figure 2; and

cooperates with seat 56at the Figure 4 is a vertical section through anoil well showing the invention applied to intermittent lift.

It is to be noted that the valve shown in Figure 2 is screwed into itssupport 90 degrees farther than as shown in Figure 1. In Figure 3, tofacilitate drafting, the orientation is as though the valve were screwedinto its support 45 degrees farther than shown in Figure 2.

Referring to Figure 1, there is shown an oil well casing If], withinwhich is disposed a string of tubing I I. Along the outside of thetubing in the annulus formed between tubing and easing there aredisposed stage lift valves l2, beneath each of which is disposed a checkvalve 13 and above each of which is disposed a guard l4. To the lowerend of the tubing is connected a strainer 15 through which the oil isadmitted to the tubing. Gas is admitted to the top of the annulus from asuitable source not shown.

Referring now also to Figures 2 and 3, each valve l2 comprises a lowerfixed housing portion 20 in the form of a cylindrical sleeve having twoupstanding sleeve sectors 2| and 22, each of 90 degrees width, and anupper movable housing portion 23 in the form of a cylindrical sleevehaving two depending sleeve sectors 24 and 25, each of 90 degrees width,the sectors of the upper and lower portions interengaging and beingrelatively slidable, i. e. reciprocable parallel to the axis of thehousing. The top end of the lower housing portion is closed by disc 26which extends between sectors 2| and 22 and is integral therewith. Thetop end of the upper housing portion is closed by disc 21 which isintegral'with the sleeve. The bottom end of the lower housing portion isclosed by nipple 28 suitably secured to the sleeve and the bottom of theupper housing portion is closed by cylinder 29 secured between and tosectors or arms 24, 25, bymeans of screws 30, 3|.

A'bellows 40 has its ends closed by plugs 4| and 42. Plug 42 is securedto disc 26 by screw M. The bellows is filled with gas under pressurethrough opening 45 in the plug 4|. A check valve 46 is screwed into theopening to prevent the gas from escaping.

Cylinder 29 carries a valve stem 50, the lower end of which is roundedto form a valve 5|. Valve 5| cooperates with valve seat 52 formed at theupper end of passage 53 through the valve body constituted by nipple 28.The nipple 28 is screwed into the top of housing 54 of check valve l3.Within the housing is a ball 55 which lower end of higher pressure than3 passage 53. A spring 51 carried in recess 58 urges the ball toward theseat. A passage 59 leads from the interior of housing 54 to a passage5!! through tubing H to which the housing is suitably secured, forexample by welding as indicated at 6|.

Valve 5| controls the admission of gas from the annulus through thevalve housing inlet apertures 625,. 63;, passage 59, and 60,, to thelnslde of the tubing.v The. valve as shown is open bu upon increase ofannulus gas pressure above the bellows pressure, the bellows contractsand the. valve closes. The check valve 55 prevents oil in the tubingfrom flowing out into the annulus when the valve 5| is open.

The bellows is initially at such internal pressure that it urges theplug 2 9 upwards against the disc 25 which serves as a stop tolimit theopening movement. Byholding the bellows contracted more. than. itsinternal pressure alone would dictate, the bellows is kept from movingwith every slight change of external pressure, which causes the valve tohave, a sharply defined closing pressure. By making the bellows fairlylong compared to the valve travel from open to closedpositionthe rangeof pressure between open andclosed position is further narrowed. The twopart telescoping housing 25-43 provides not only a. stop for limitingthe valve travel but affords excellent, protection the bellows and thevalve. and seat. The valve travel is such that in both open and closedpositions there is ample space between the ends of the arms and thebodies oi the housing portions to admit gas to the side of the bellowsand to the valve. The lower. gas ports 52; 5.3 insure that no sand cancollect in the lower part of thehous-ing and: there are no pockets inthe upperpart of the housing for sand to collect in either.

Referring to Figure 1-, there will bea plurality of stage lift valvesdisposed along the side of the tubing at approximately equal intervals;hydrostatic head; of oil between each pair of successive valves beinsomewhat less than the pressure of the as available foradmission tothe:annulus. The bellows of each valve will becharged to a the valve above.With: this arrangement of valves, gas will. be initially admitted to theannulus at a. pressure belowthat required to closethe uppermost valvebut higher than the hydrostatic pressure of the: all thereabove. The oilis at a higher level than the uppermost valve, will be forced downthrough the law-6 111505118 tubing until the valve is exposed; Gas willthen enter-the tubing through the valve andiwillemulsify-and lighten theoil column so that it will rise tothe surface and: flow out. As: soon.as: enough oil has thus been removed above the top valve, the annuluspressure will. be increased. enough to close the top valve and torovercome the hydro..- static head of the oil above the.second'valvedoivn from the top, including-both. the emulsion above the first valveand: the dead oil! therebelow. When this. columnlhas. beensufl'icientlylightened the pressure in the annulus. will be. furtherin.- creased enough to close the: second valve and to overcome the head:of theoils above: the; third valve, including both the light emulsion.above the second valve and the heavy: dead oil therebelow. This. processwill be continued, until gas is being admitted to: the tubing at. apointlow enough so that the gas does not cutithrough the oil but all is mixedwith the oil. as an emulsion: The gas is then said to havesufiicientsubmerin the annulus, which initially gence. The oil-gas emulsion flowsto the surface continuously at a minimum gas-oil ratio. The pressure maybe increased further to admit the oil at a still lower point if it isdesired to further lighten the column to increase the rate of flow.Since the pressure in increased as the gas admission point is lowered,all valves above that through which gas is being admitted are positivelyclosed. This prevents cutting. of the valve as would; be the case: if itwere cracked partly open. At the same time the valve through which gasis admitted, bein normally open is fully open and is not out either.Thevalve and stage lift system according to the invention can also beused with an intermittent lift operation as shown in Figure 4. Inaddition to the. apparatus of Figure 1 there is also shown anaccumulation chamber 10, a packer H between the tubing and annulus, anda normally closed bellows actuated valve 12. The stage lift valves havesufficiently large! openings so. that a; large quantity. of gas. flows:through each when. it: is open. This. causes, the oil above it1to. riseas. a slu instead. of emulsifying and: the. tubing above szleiit:completely dry.. After the oil is kickedoif m slugs downtothe level: ofthe lowermost valve, the gas pressure is raised.- enough to open valvei=2: and raise the oil in the accumulation chamber 1:0; Thereafter-theintermitter control. device 5.31 at; the. surta-ce lowers the-annulusgas pressure to close valve 12; until. the accumulation chamber hasfilled again. whereupon. the pressure is increased. to=again empty the:chamber. Ball check valve Mileeeps; the gas pressureoff the formation 1.5 during; the lifting of the oil to the. surface fromthecha-mben Valve12- may be of. any conventional type such as that shown in,U-.. S.Patent 2,339,487, granted January is, 19.4mm wn. King.

While preferred embodiments. of the: invention have been;shown anddescribed, itis obvious that many modifications, thereof could; be madebyone sk ll ed in the art. without departing fromthe spirit of theinvention. and. it. is; intended topro tect by letters. patent all,forms of. the; invention falling within thescope'of-the followingclaimsi I claim:

l. Astage liftvalvecomprising a. threaded nip.- ple having a valve seatformed; at; one end, a first sleeve. secured to the, nipple: andextending; beyondsaidseata pair of oppositely. disposed.- arms extendingfrom said. sleeve. away from said. seat, a. closed bellows having; one,-end secured to.- said arms, the; bodyofthe, bellows. extending away fromsaid, seat, a. second sleeve having one. end secured. to the other. endof. said, bellows, said sleeve. extendingebacle around saidbellowstowardsaid seat,,a. pair of oppositely disposed. arms extending; from. the.other end of saidbellows. to, ward said: seat andreciprocatinglyslidinglvins teren aging with. thefirst, said arms}, anda. valve secured to the ends of the arms of. the second sleeve. andadaptedto, engage. said. seat, said. bellows. containing gas at, a.pressure above atmosr pheric so as to normally hold said valve. openposition. awav from itsiseat- 2.. Astageliftvalve comprisingv asealedbellows containing;- gas under pressure, a first cylindrical housingportion surrounding. the bellows. and. secured. thereto at one: end,,said. housing. having, a plurality of slots in itsother, end leaving;arms of arcuate; cross: section; therebetween, a cylindrical; plug;received between the; ends of. said arms. and; secured theretm. avalvestem carried by said plug extending away from said bellows,

a valve member formed on the end of said stem, a nipple having a valveseat formed therein adapted to cooperate with said valve member, asecond cylindrical housing portion surrounding said valve member andseat, said second housing portion being secured to said nipple, saidsecond housing portion having apertures therethrough adjacent said seatand having a plurality of slots in its other end leaving arms of arcuatecross section therebetween, the last said arms fitting in the first saidslots and the first said arms fit-- ting in the last said slots so thatthe two housing portions together form a single extensible andretractable housing, and a disc integral with the ends of the secondsaid arms secured to the other end of said bellows between said bellowsand said plug.

3. A stage lift device comprising a sealed bellows containing gas underpressure, a first cylindrical housing portion and secured thereto at oneend, said housing having a plurality of slots in its other end leavingarms of arcuate cross section therebetween, a cylindrical plug receivedbetween the ends of said arms and secured thereto, a valve stem carriedby said plug extending away from said bellows, a valve member formed onthe end of said stem, a nipple having a valve seat formed thereinadapted to cooperate with said valve member, a second cylindricalhousing portion surrounding said valve member and seat, said secondhousing portion being secured to said nipple, said second housingportion having apertures therethrough adjacent said seat and having aplurality of slots surrounding the bellows in its other end leaving armsof arcuate cross section therebetween, the last said arms fitting in thefirst said slots and the first said arms fitting in the last said slotsso that the two housing portions together form a single extensible andretractable housing, a disc integral with the ends of the second saidarms secured to the other end of said bellows between said bellows andsaid plug, an opening through the first said end of the bellows and anopening through the end of the housing portion connected thereto, acheck valve secured in the first said opening, a screw through thesecond said opening engaging a thread in the second said opening toclose the openings and secure the bellows to said housing portion asaforesaid, a support adapted to be secured to the side of a well tubing,a passage through said support having openings disposed at an angle toeach other, one of said openings receiving therein and being secured tothe end of said nipple away from said valve member, and a ball checkvalve disposed in said one of said openings between said support andnipple.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 19,711 Simmons Sept. 17, 1935 2,184,636 Crickmer et al.Dec. 26, 1939 2,292,768 Parker Aug. 11, 1942 2,342,301 Peters Feb. 22,1944 2,465,060 Carlisle Mar. 22, 1949 2,594,831 Walton Apr. 29, 1952

